The present invention relates to an adhesive, and more particularly to an adhesive which changes to a strongly securable condition from a peelable condition when water is applied thereto.
Various kinds of pressure-sensitive adhesives are known for various applications, which are broadly classified into weak adhesives and strong adhesives. Among the weak adhesives, there are peelable pressure-sensitive adhesives which are peelable after being attached and can be attached again. However, these conventional adhesives have but a single adhesive power and property which causes a certain inconvenience in use. For example, when the peelable pressure-sensitive adhesive is applied to the back of a photographic print for attaching the photographic print to an album sheet, the photographic print can be peeled off if desired. However, when it is necessary to attach the photographic print permanently or strongly, a different, strong adhesive has to be coated on the peelable adhesive previously applied on the back of the photographic print.